The Java EE 6 Tutorial

What Is a Servlet?

A servlet is a Java programming language class used to extend the capabilities of servers that host applications accessed by means of a request-response programming model. Although servlets can respond to any type of request, they are commonly used to extend the applications hosted by web servers. For such applications, Java Servlet technology defines HTTP-specific servlet classes.

The

javax.servlet

and

javax.servlet.http

packages provide interfaces and classes for writing servlets. All servlets must implement the

Servlet

interface, which defines lifecycle methods. When implementing a generic service, you can use or extend the

GenericServlet

class provided with the Java Servlet API. The

HttpServlet

class provides methods, such as

doGet

and

doPost

, for handling HTTP-specific services.